Jesus Christ made it clear: His first coming was meant to draw the world into two teams:
So if His kingdom is not of this world, then this world is on Team Satan. If Satan is a liar and a murderer from the beginning, then he will even lie about his own existence because he has nothing to lose.
Satan chose his path, and if our Heavenly Father told us to forgive our enemies 70 times 7 times, then He most likely gave Lucifer several chances to repent. The only conclusion we can come to is that Lucifer decided not to repent. He was at the right hand of God’s throne as a Covering Archangel, meaning his job was to cover up the throne of the Almighty (not music, as many think – who’s going to follow a music person into rebellion?). Heaven is an orderly place, so angels of lesser rank who needed to approach God’s throne had to go through Lucifer. Over time, controlling this access to the throne may have gone to Lucifer’s head, making him arrogant and increasingly boastful.